In reply to ribtech: just train climbing with a really static style. A drill you can do for this is have your belayer shout 'stop' at random and you have to hold the exact position you're in for a few seconds.

No. Climbing wall holds spin when they are loose - which can hurt your wrists. Loose rock just comes off (or if you're lucky moves a bit then stops!). Like Jon says, pushing rather than pulling on the rock works well. Just be really smooth and delicate. Be sure to tap/ whack holds to see if they sound loose/ move. For low angled stuff, it may be good training to practice climbing with a tennis ball in each hand (a game I've heard of but never tried).